Linq基本语法

 //从老集合中查询每一个元素d存入新集合
            var list = from d in list_dog select d;
            //编译后会生成对应的标准查询运算符 linq是一种类似于sql 标准的语法糖
            list = from d in list_dog where d.Gender==false select d;
            //排序
            list = from d in list_dog orderby d.ID ascending orderby d.Age descending select d;
            //连接查询
            var listjoin = from d in list_dog join dt in list_dogtoy on d.ID equals dt.ID_Dog select new { Name = d.Name, ToyName = dt.Name };
            //group by
            var list_groupby = from d in list_dog group d by d.Gender;